There is a risk of severe thunderstorm activity in the Northeast on Wednesday.
Forecast overview for Connecticut:
Tuesday night: Periods of rain with patchy fog.
Wednesday: Warm/humid, showers & thunderstorms, becoming more numerous by late afternoon.
Wednesday night: Showers and thunderstorms continuing.
Low threat (Conditions are somewhat favorable for severe thunderstorms)
Interior New England, New York, northwestern New Jersey and northern Pennsylvania:
A warm front lifts through the area on Wednesday from southwest to northeast. As the front clears, a warm, moist and more unstable air-mass floods into the Northeast. Once lingering showers, patchy fog and drizzle clear, some daytime heating will begin to fuel the atmosphere. The severe thunderstorm threat relies on a few factors. Although daytime heating is important, it should be noted that bulk wind shear values are forecast to be low to moderate, with the strongest helicity displaced northeast into central and northern New England.
A trough during the afternoon and early evening hours works as a trigger mechanism for thunderstorm development. The focus is on central and eastern New York, as well as western Massachusetts and southern Vermont. This area has a fair amount of overlap with respect to wind shear, instability, helicity and proximity to a shortwave passing near the Canadian-United States border.
It is also in this region that both the ARW and NMM model forecast reflectivities indicate a relatively strong squall line dropping southeast between about 5 p.m. and 9 p.m. local time.
The threat appears to be mainly strong winds, but isolated hail is another possibility. Although the tornado threat is low, should wind shear coincide enough with higher helicity values, there could be a spin up or two.
This area is being monitored and may be upgraded to a moderate threat of severe thunderstorms, should model guidance trends continue.
Marginal threat (Conditions are marginally favorable for severe thunderstorms)
Elsewhere in green:
A few scattered showers and thunderstorms are possible across the region, as far south as the middle Appalachians. Across the coastal plain of New England, decaying thunderstorms could hold together as they approach Interstate 95.
Threat definitions…(Severe thunderstorm = wind gusts to 58 MPH and/or >1″ hail)
Marginal: Conditions are marginally favorable for severe thunderstorms.
Low: Conditions are somewhat favorable for severe thunderstorms.
Moderate: Conditions are moderately favorable for severe thunderstorms.
High: Conditions are very favorable for severe thunderstorms.
Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely.
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